Pirated versions on torrent sites is not the way to go nor is such a thing endorsed here.
As far as where to get it. The proper and legal option is to go through a Mimaki dealer, order and pay for a newer version if you want a newer version. Like the majority of us - doing things right is part of the cost of doing business. I personally wish those using pirated software etc to fail miserably and go out of business. Using illegal pirated software is an unfair financial advantage.